DOCSLIB.ORG

The Book of Postfix

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Book of Postfix THE BOOK OF™ POSTFIX State-of-the-Art Message Transport by Ralf Hildebrandt and Patrick Koetter San Francisco THE BOOK OF POSTFIX. Copyright © 2005 by Ralf Hildebrandt and Patrick Koetter. All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval system, without the prior written permission of the copyright owner and the publisher. Printed on recycled paper in the United States of America 1 2 3 4 5 6 7 8 9 10 – 07 06 05 04 No Starch Press and the No Starch Press logo are registered trademarks of No Starch Press, Inc. The Book of is a trademark of No Starch Press, Inc. Other product and company names mentioned herein may be the trademarks of their respective owners. Rather than use a trademark symbol with every occurrence of a trademarked name, we are using the names only in an editorial fashion and to the benefit of the trademark owner, with no intention of infringement of the trademark. Publisher: William Pollock Managing Editor: Karol Jurado Production Manager: Susan Berge Cover and Interior Design: Octopod Studios Developmental Editor: Brian Ward Technical Reviewer: Brian Ward Copyeditor: Andy Carroll Compositor: Riley Hoffman Proofreader: Stephanie Provines Indexer: Kevin Broccoli For information on book distributors or translations, please contact No Starch Press, Inc. directly: No Starch Press, Inc. 555 De Haro Street, Suite 250, San Francisco, CA 94107 phone: 415.863.9900; fax: 415.863.9950; [email protected]; http://www.nostarch.com The information in this book is distributed on an “As Is” basis, without warranty. While every precaution has been taken in the preparation of this work, neither the author nor No Starch Press, Inc. shall have any liability to any person or entity with respect to any loss or damage caused or alleged to be caused directly or indirectly by the information contained in it. Library of Congress Cataloging-in-Publication Data Hildebrandt, Ralf. The book of Postfix : state-of-the-art message transport / Ralf Hildebrandt and Patrick Koetter. p. cm. ISBN 1-59327-001-1 1. Postfix (Computer file). 2. Electronic mail systems--Computer programs. 3. Internet. I. Koetter, Patrick. II. Title. TK5105.74.P66H55 2005 005.7'13--dc22 2003017563 No Starch Press, Copyright © 2005 by Ralf Hildebrandt and Patrick Koetter To those who like good software No Starch Press, Copyright © 2005 by Ralf Hildebrandt and Patrick Koetter ABOUT THE AUTHORS Ralf Hildebrandt and Patrick Koetter are active and well-known figures in the Postfix community. Hildebrandt is a manager technics for T-Systems, a German information and communications technology (ICT) solutions company. Koetter is an information architect running his own company consulting and developing corporate communication for customers in Europe and Africa. Both have spoken about Postfix at industry conferences and hacker conventions and contribute regularly to a number of open source mailing lists. No Starch Press, Copyright © 2005 by Ralf Hildebrandt and Patrick Koetter ACKNOWLEDGMENTS There are a lot of people we need to thank for this book, so we’ll each give our lists. Ralf Hildebrandt One thing I noticed while writing this book was how little I knew about how Postfix works “under the hood.” I knew how it behaved, but not exactly why, at least not in every single component and corner-case. In some cases I didn’t know much, in other areas I found my knowledge (or lack thereof) to be wrong. I had to RTFM and ask a lot of questions on the helpful postfix-users mailing list to get the details. This book will not be able to replace the experience of running Postfix for more than five years, but it will lead you closer to mastering it. Admittedly, when I started with Unix in ’94, the Internet was a much safer place than it is now. There wasn’t any spam! I only got to know Postfix because Sendmail kept crashing on me. After a brief interlude with qmail, I found Postfix and stuck with it. I never looked back. When Bill approached me and asked if I wanted to write a book about Postfix, I hesitated at first. I needed a co-author, since the sheer amount of work to be done was far too much for one person. At that time, Patrick was cursing SASL on the list and vowed to write a SASL-HOWTO if he ever got it working. He did, and I read the HOWTO, liked it, and asked him for his co- authorship. As it turns out, the amount of work was too much even for two people, so Brian Ward joined us as a technical editor, adding valuable experience in areas where we lacked it. Without the help of Wietse Venema, Vi(c|k)tor Duchovni, Lutz Jänicke, Andreas Winkelmann, and Peter Bieringer, this book would have never reached its present state, so they’re in for a free copy. Not that they need it, but it sure makes a great gift. A big thanks and love go to my wife Constanze No Starch Press, Copyright © 2005 by Ralf Hildebrandt and Patrick Koetter who endured my frequent “But I still have to write a chapter now!” excuses and thus made it possible to finish the book instead of letting it become vaporware. Oh yeah, and when reading Patrick’s comments, please keep in mind that I’m only slightly crazy. Patrick Koetter Years will pass before the Internet provides us with all the services we want it to have. Just as with any other new medium, the immediate impulse of those who provide services is to push growth, especially in the quantity of content and services. The quality of the service and its functionalities usually has to stand back—at least until the service starts to pay off. In the meantime it is exposed to people who like to abuse and destroy things rather than promote and expand them. This has happened to email and this is where Postfix comes in, and really does provide a new dimension of quality. When I went out to get myself an SMTP server, I was shocked that Sendmail seemed to require a diploma of some sort, especially to figure out the macros. So I looked around for other software. To cut it short: I fell in love with Postfix. Postfix showed me that it’s possible to have complex software configured with a simple, clear, and structured syntax. If you know SMTP, you already know most of the important details of configuring Postfix. I didn’t really know SMTP when Ralf asked me to write the book with him. This book required me to learn more than I had expected and to correct misunderstandings. I am very proud that this book gives me the opportunity to hand over what I know about computers and email today. Hopefully this book will get you well on your way to using Postfix creatively. Creativity grows the best when there is knowledge. This book would not have seen the light without the knowledge, curiosity, and support of Wietse Venema, Vi(c|k)tor Duchovni, Liviu Daia, Lutz Jänicke, Florian Kirstein, Walter Steinsdorfer, Roland Rollinger, Tom Thomas, Alexey Melnikov, Andreas Winkelmann, Eric “cybertime hostmaster,” and the users of the Postfix mailing list; their questions and problems told us what was missing when we thought everything had been said. Most importantly, I need to thank Ralf, whose knowledge about Postfix is outclassed only by his sassy use of computers. He’s like a duck taking to water in this respect. It was Ralf who chose me to be his companion on this adven- ture called The Book of Postfix, and I’m indebted to this crazy guy who became a close friend as we wrote this book. The book has been a great challenge, not only to me, but also to my wife Birgit; her trust in me carried me through the countless lines of this book. It’s a great privilege to be asked to do something that you’ve set your heart on. It’s a godsend to have somebody like Birgit at your side when you finally do it. viii Acknowledgments No Starch Press, Copyright © 2005 by Ralf Hildebrandt and Patrick Koetter BRIEF CONTENTS About This Book Chapter 5 xxv Anatomy of Postfix 35 Chapter 1 An Introduction to Postfix Part II: Content Control 1 Chapter 6 Part I: Basics A Postmaster’s Primer to Email 55 Chapter 2 Preparing Your Host and Chapter 7 Environment How Message Transfer 7 Restrictions Work 69 Chapter 3 Mail Server for a Single Domain Chapter 8 17 Using Message Transfer Restrictions Chapter 4 81 Dial-up Mail Server for a Single Domain Chapter 9 29 How Built-in Content Filters Work 111 No Starch Press, Copyright © 2005 by Ralf Hildebrandt and Patrick Koetter Chapter 10 Chapter 16 Using Built-in Content Filters SMTP Authentication 117 247 Chapter 11 Chapter 17 How External Content Understanding Filters Work Transport Layer Security 129 267 Chapter 12 Chapter 18 Using External Content Filters Using Transport Layer Security 141 279 Chapter 19 Part III: Advanced A Company Mail Server Configurations 313 Chapter 13 Mail Gateways Chapter 20 169 Running Postfix in a chroot Environment 369 Chapter 14 A Mail Server for Multiple Domains Part IV: Tuning Postfix 189 Chapter 21 Chapter 15 Remote Client Concurrency Understanding SMTP and Request Rate Limiting Authentication 379 217 Chapter 22 Performance Tuning 387 x Brief Contents No Starch Press, Copyright © 2005 by Ralf Hildebrandt and Patrick Koetter Appendices Appendix C CIDR and SMTP Standards Appendix A Reference Installing Postfix 435 407 Glossary Appendix B 441 Troubleshooting Postfix 419 Index 449 Brief Contents xi No Starch Press, Copyright © 2005 by Ralf Hildebrandt and Patrick Koetter No Starch Press, Copyright © 2005 by Ralf Hildebrandt and Patrick Koetter CONTENTS IN DETAIL ABOUT THIS BOOK xxv Additional Resources .............................................................................................xxvi Postfix Documentation, How-tos, and FAQs .................................................xxvi Mailing Lists ............................................................................................xxvi Conventions Used in This Book ..............................................................................xxvii Domains and Names Used in This Book .................................................................
Load more

Recommended publications
  • CYRUS: BUILD YOUR TUTORIAL OWN EMAIL SERVER Don’T Trust Google? We’Ll Help You Navigate the Sea of JOHN LANE Acronyms to Build Your Own Mailserver
    TUTORIAL MAILSERVER CYRUS: BUILD YOUR TUTORIAL OWN EMAIL SERVER Don’t trust Google? We’ll help you navigate the sea of JOHN LANE acronyms to build your own mailserver. ou can’t beat the convenience and ease of use access their mail by connecting to the server using WHY DO THIS? offered by Gmail. But unfortunately, all that any IMAP-capable email client application. • Take control of your Yfree storage comes at a price: your privacy. You will need a, preferably new, server for this email provision. Spam, intrusive adverts and snooping from unnamed project and you’ll need root access to it. Our examples • Stop outside agencies government agencies are the inevitable downside of use Arch Linux, and we created a new virtual server. from scanning the using someone else’s service for free. So why not Begin by installing Cyrus (build the Arch User content of your emails. build your own email server including anti-spam, Repository package first – see the boxout below-right): • Get webmail without advertising. anti-virus and webmail? $ pacman -U ~build/cyrus-imapd/cyrus-imapd-2.4.17-5-x86_64. You can use your own server to retrieve messages pkg.tar.xz from other mailservers, such as those provided by The default configuration writes data to /var/imap internet service providers, or other services like those and user mailboxes to /var/spool/imap. You can from Google and Yahoo. But you don’t need to rely on change this if you prefer another location; we’ll others if you have your own server. If you have a configure our server to use /srv/mail/cyrus to domain name that you control, and if you can give your illustrate this.
    [Show full text]
  • Oldschool E-Mail Setup Eine Freakshow
    Oldschool E-mail Setup Eine Freakshow [email protected] Chemnitzer Linuxtage, 2016 (Screenshot GMX vor >15 Jahren: Waybackmachine zu www.gmx.net) (Screenshot GMX heute) (Screenshot Gmail heute) Lösungen? ● Claws ● Mutt ● Eudora ● Netscape Navigator ● Evolution ● Opera M2 ● GMX ● Outlook ● Gnus ● SquirrelMail ● Hotmail ● The Bat! ● Hushmail ● Thunderbird ● KMail ● … Flußgrafik Email Netz MTA MRA MDA MUA MSA MTA Netz Hipster! ● KISS ● YAGNI ● DRY ● NIH ● Divide And Conquer ● Everything is a file ● No vendor lock-in ● Mißtraue Autoritäten – fördere Dezentralisierung Netz Netz Emails Client, den ich Remote verwenden kann Leicht erweiterbar Emails lokal Filter Offenes Format Adressen Netz Netz Abholen Transportformat? Pull Subject 1 Email = 1 File Keine Spuren X-List-ID Mit Hierarchien am Server Beliebige Einfaches Suchen Header Verlässliches Suchen Verarbeitung mit Unix Tools Client, den ich Remote verwenden kann Leicht erweiterbar Emails lokal Filter Offenes Format Adressen Netz Netz Abholen Transportformat? Pull Subject 1 Email = 1 File Keine Spuren X-List-ID Mit Hierarchien am Server Beliebige Einfaches Suchen Header Verlässliches Suchen Verarbeitung mit Unix Tools mbox Maildir mh Client, den ich Remote verwenden kann Leicht erweiterbar Emails lokal Filter Offenes Format Adressen Netz Netz Abholen Transportformat? Pull Subject 1 Email = 1 File Keine Spuren X-List-ID Mit Hierarchien am Server Beliebige Einfaches Suchen Header Verlässliches Suchen Verarbeitung mit Unix Tools mbox Maildir mh tmp 1439306571.1269_0.elvis ~/Post/Technik/Wikitech new 1448267819.5940_0.spencer ... 1457079728.2000_0.spencer:2, cur 1456839383.9873_0.nepomuk:2,SR 1457166567.23654_0.spencer:2,S ... Client, den ich Remote verwenden kann Leicht erweiterbar Filter Adressen Netz Netz Abholen Pull Subject Maildir Keine Spuren X-List-ID am Server Beliebige Header Client, den ich Remote verwenden kann Leicht erweiterbar Filter Adressen Netz Netz Abholen Pull Subject Maildir Keine Spuren X-List-ID am Server Beliebige Header fetchmail getmail mpop ..
    [Show full text]
  • Resurrect Your Old PC
    Resurrect your old PCs Resurrect your old PC Nostalgic for your old beige boxes? Don’t let them gather dust! Proprietary OSes force users to upgrade hardware much sooner than necessary: Neil Bothwick highlights some great ways to make your pensioned-off PCs earn their keep. ardware performance is constantly improving, and it is only natural to want the best, so we upgrade our H system from time to time and leave the old ones behind, considering them obsolete. But you don’t usually need the latest and greatest, it was only a few years ago that people were running perfectly usable systems on 500MHz CPUs and drooling over the prospect that a 1GHz CPU might actually be available quite soon. I can imagine someone writing a similar article, ten years from now, about what to do with that slow, old 4GHz eight-core system that is now gathering dust. That’s what we aim to do here, show you how you can put that old hardware to good use instead of consigning it to the scrapheap. So what are we talking about when we say older computers? The sort of spec that was popular around the turn of the century. OK, while that may be true, it does make it seem like we are talking about really old hardware. A typical entry-level machine from six or seven years ago would have had something like an 800MHz processor, Pentium 3 or similar, 128MB of RAM and a 20- 30GB hard disk. The test rig used for testing most of the software we will discuss is actually slightly lower spec, it has a 700MHz Celeron processor, because that’s what I found in the pile of computer gear I never throw away in my loft, right next to my faithful old – but non-functioning – Amiga 4000.
    [Show full text]
  • DMARC — Defeating E-Mail Abuse
    CERT-EU Security Whitepaper 17-001 DMARC — Defeating E-Mail Abuse Christos Koutroumpas ver. 1.3 February 9, 2017 TLP: WHITE 1 Preface E-mail is one of the most valuable and broadly used means of communication and most orga- nizations strongly depend on it. The Simple Mail Transport Protocol (SMTP) – the Internet’s underlying email protocol – was adopted in the eighties and is still in use after 35 years. When it was designed, the need for security was not so obvious, and therefore security was not incor- porated in the design of this protocol. As a result, the protocol is susceptible to a wide range of attacks. Spear-phishing campaigns in particular can be more successful by spoofing (altering) the originator e-mail address to imper- sonate a trusted or trustworthy organization or person. This can lead to luring the recipient into giving away credentials or infecting his/her computer by executing malware delivered through the e-mail. While raising user awareness on how to avoid e-mail fraud is recommended, the Verizon Data Breach Investigations Report indicates that more needs to be done. The DBIR report reveals that 30% of all phishing e-mail messages were opened by the recipients and with 12% clicked on the content and executed malicious code. The median time for the first user of a phishing campaign to open the malicious email is 1 minute, 40 seconds. The median time to the first click on the attachment was 3 minutes, 45 seconds. These statistics highlight the risk for an organization on the receiving end of spear-phishing e-mails.
    [Show full text]
  • Design Document
    SPEC OSG Mailserver Subcommittee SPECmail2009 Benchmark Architecture White Paper Revision: v1.0 Date: 22 December 2008 Copyright © 2001-2009 Standard Performance Evaluation Corporation. All Rights Reserved. 1. Introduction 1.1 Overview SPECmail2009 is a software benchmark designed to measure a system's ability to act as an enterprise mail server servicing email requests, based on the Internet standard protocols SMTP and IMAP4. The benchmark concentrates on the workload encountered by corporate mail servers, with an overall user count in the range of 150 to 10,000 (or more) users. It models IMAP business users accessing IMAP servers over fast local area networks (LAN) instead of broadband, WAN or dialup access speeds. Two separate metrics measure e-mail servers with and without secure network connections (SSL). SPECmail2009 has been developed by the Standard Performance Evaluation Corporation (SPEC), a non-profit group of computer vendors, system integrators, universities, research organizations, publishers, and consultants. This paper discusses the benchmark principles and architecture, and the rationale behind the key design decisions. It also outlines the workload used in the benchmark, and the general steps needed to run a benchmark. However those aspects are covered in more detail in other documents. 1.2 Organization of this Paper Chapter 2 discusses the basic goals and non-goals of the benchmark. Chapter 3 introduces the two performance metrics for SPECmail2009 – IMAP sessions per hour - and how it relates to the transaction mix imposed on the system under test.. Chapter 4 explains the benchmark workload - how it was derived, how it translates into configuration parameters for the benchmark tool and size calculations for planning a benchmark, and how it relates to the benchmark metric.
    [Show full text]
  • Business SITUS Address Taxes Owed # 11828201655 PROPERTY HOLDING SERV TRUST 828 WABASH AV CHARLOTTE NC 28208 24.37 1 ROCK INVESTMENTS LLC
    Business SITUS Address Taxes Owed # 11828201655 PROPERTY HOLDING SERV TRUST 828 WABASH AV CHARLOTTE NC 28208 24.37 1 ROCK INVESTMENTS LLC . 1101 BANNISTER PL CHARLOTTE NC 28213 510.98 1 STOP MAIL SHOP 8206 PROVIDENCE RD CHARLOTTE NC 28277 86.92 1021 ALLEN LLC . 1021 ALLEN ST CHARLOTTE NC 28205 419.39 1060 CREATIVE INC 801 CLANTON RD CHARLOTTE NC 28217 347.12 112 AUTO ELECTRIC 210 DELBURG ST DAVIDSON NC 28036 45.32 1209 FONTANA AVE LLC . FONTANA AV CHARLOTTE 22.01 1213 W MOREHEAD STREET GP LLC . 1207 W MOREHEAD ST CHARLOTTE NC 28208 2896.87 1213 W MOREHEAD STREET GP LLC . 1201 W MOREHEAD ST CHARLOTTE NC 28208 6942.12 1233 MOREHEAD LLC . 630 402 CALVERT ST CHARLOTTE NC 28208 1753.48 1431 E INDEPENDENCE BLVD LLC . 1431 E INDEPENDENCE BV CHARLOTTE NC 28205 1352.65 160 DEVELOPMENT GROUP LLC . HUNTING BIRDS LN MECKLENBURG 444.12 160 DEVELOPMENT GROUP LLC . STEELE CREEK RD MECKLENBURG 2229.49 1787 JAMESTON DR LLC . 1787 JAMESTON DR CHARLOTTE NC 28209 3494.88 1801 COMMONWEALTH LLC . 1801 COMMONWEALTH AV CHARLOTTE NC 28205 9819.32 1961 RUNNYMEDE LLC . 5419 BEAM LAKE DR UNINCORPORATED 958.87 1ST METROPOLITAN MORTGAGE SUITE 333 3420 TORINGDON WY CHARLOTTE NC 28277 15.31 2 THE MAX SALON 10223 E UNIVERSITY CITY BV CHARLOTTE NC 28262 269.96 201 SOUTH TRYON OWNER LLC 201 S TRYON ST CHARLOTTE NC 28202 396.11 201 SOUTH TRYON OWNER LLC 237 S TRYON ST CHARLOTTE NC 28202 49.80 2010 TRYON REAL ESTATE LLC . 2010 S TRYON ST CHARLOTTE NC 28203 3491.48 208 WONDERWOOD TREE PRESERVATION HO .
    [Show full text]
  • Znetlive SSL Compatible Applications, Platforms & Operating
    ZNetLive SSL Compatible Applications, Platforms & Operating Systems Certificate Authority Root Apple MAC OS 9.0+ (circa 2002), includes 10.5.X and 10.6.X Future proof at 2048 bit, embedded in all Microsoft Windows XP, Vista, 7 and 8 (all devices and browsers and capable of upgrading versions inc 32/64 bit) weak encryption to a strong one is the most reliable Certificate Authority Root-GlobalSign. It is very important to ensure a flawless interaction of your online solutions with Default API Support within Hosting Control customers making connection with your web Panels server, reading emails, trusting your e- Ubersmith documents or running your code. Every WHMCS standard machine that uses trust of Public Key Infrastructure (PKI), e.g. S/MIME, SSL/TLS, Document Signing and Code Signing, has GlobalSign’s Root Certification present in it. Email Clients (S/MIME) ZNetLive’s SSL Certificates authenticated by GlobalSign have 2048 bit strength throughout Mulberry Mail complete Digital Certificate portfolio and Microsoft Outlook 99+ comply with recommendations of National Microsoft Entourage (OS/X) Institute of Standards and Technology (NIST) Qualcomm Eudora 6.2+ according to which all cryptographic keys Mozilla Thunderbird 1.0+ should be 2048 bit strength from 2011 onwards. Mail.app Anything weaker than 2048 bit encryption is Lotus Notes (6+) considered insecure. Because of this, the Netscape Communicator 4.51+ Certification Authorities and Browsers insists The Bat that all the EV SSL Certificates should be 2048 Apple Mail bit encryption.
    [Show full text]
  • Cyrus Mail Server 2 Table of Contents
    Univention Corporate Server Cyrus mail server 2 Table of Contents 1. Introduction ........................................................................................................................ 4 2. Installation ......................................................................................................................... 5 3. Management of the mail server data ....................................................................................... 6 3.1. Management of mail domains ..................................................................................... 6 3.2. Assignment of e-mail addresses to users ........................................................................ 6 3.3. Management of mailing lists ....................................................................................... 7 3.4. Management of mail groups ........................................................................................ 7 3.5. Management of shared IMAP folders ........................................................................... 8 3.6. Mail quota ............................................................................................................... 9 4. Spam detection and filtering ................................................................................................ 10 5. Identification of viruses and malware .................................................................................... 11 6. Identification of Spam sources with DNS-based Blackhole Lists (DNSBL) ...................................
    [Show full text]
  • Toward an Automated Vulnerability Comparison of Open Source IMAP Servers Chaos Golubitsky – Carnegie Mellon University
    Toward an Automated Vulnerability Comparison of Open Source IMAP Servers Chaos Golubitsky – Carnegie Mellon University ABSTRACT The attack surface concept provides a means of discussing the susceptibility of software to as-yet-unknown attacks. A system’s attack surface encompasses the methods the system makes available to an attacker, and the system resources which can be used to further an attack. A measurement of the size of the attack surface could be used to compare the security of multiple systems which perform the same function. The Internet Message Access Protocol (IMAP) has been in existence for over a decade. Relative to HTTP or SMTP, IMAP is a niche protocol, but IMAP servers are widely deployed nonetheless. There are three popular open source UNIX IMAP servers – UW-IMAP, Cyrus, and Courier-IMAP – and there has not been a formal security comparison between them. In this paper, I use attack surfaces to compare the relative security risks posed by these three products. I undertake this evaluation in service of two complementary goals: to provide an honest examination of the security postures and risks of the three servers, and to advance the study of attack surfaces by performing an automated attack surface measurement using a methodology based on counting entry and exit points in the code. Introduction Contributions and Roadmap System administrators frequently confront the The paper makes two major contributions. First, problem of selecting a software package to perform a I undertake an in-depth discussion of the relative secu- desired function. Many considerations affect this deci- rity postures of the three major open source IMAP sion, including functionality, ease of installation, soft- servers in use today.
    [Show full text]
  • Downloadable Email Program for My Pc 32 Best Free Email Clients
    downloadable email program for my pc 32 Best Free Email Clients. Here are 32 best free email client software . These let you manage and access all of your email accounts in one single place easily. All these email client software are completely free and can be downloaded to Windows PC. These free software offer various features, like: can be used with IMAP, SMTP, POP3 and Gmail, keeps your emails safe and secure, lets you open various emails simultaneously, provide protection from spam, lets you view your emails offline, manage and access all of your email accounts in one single place, supports PH, LDAP, IMAP4, POP3 and SMPT mail protocols etc. So, go through this list of free email client software and see which ones you like the most. Thunderbird. Thunderbird is a free and handy email client software for your computer. It can be used with IMAP, SMTP, POP3 and Gmail. It will also work with email accounts provided by MS Exchange Server. The user interface of Thunderbird is tabbed. It lets you open various emails simultaneously. Thunderbird keeps your emails safe and secure. It also has special filters for filtering the mail. Windows Live Mail. Windows Live Mail is a free email client for your computer. It works with various email accounts. It lets you access Yahoo, Gmail, Hotmail and emails from different servers which supports POP3 and SMTP. Its security features are excellent it will also provide protection from spam. You can also view your emails offline in this freeware. Zimbra Desktop. Zimbra Desktop is a free email client.
    [Show full text]
  • Symantec White Paper
    QUARTERLY REPORT: SYMANTEC ENTERPRISE SECURITY SYMANTEC REPORT: QUARTERLY Symantec Intelligence Quarterly July - September, 2009 Published October 2009 Technical Brief: Symantec Enterprise Security Symantec Intelligence Quarterly July - September, 2009 Contents Introduction . 1 Highlights . 2 Metrics. 2 Meeting the Challenge of Sophisticated Attacks . 8 Timeline of a zero-day event . 8 How secure are security protocols?. 11 Why attackers use packers. 14 Protection and Mitigation . 16 Appendix A—Best Practices . 18 Appendix B—Methodologies. 20 Credits . 24 Symantec Intelligence Quarterly July - September, 2009 Introduction Symantec has established some of the most comprehensive sources of Internet threat data in the world through the Symantec™ Global Intelligence Network. More than 240,000 sensors in over 200 countries monitor attack activity through a combination of Symantec products and services such as Symantec DeepSight™ Threat Management System, Symantec™ Managed Security Services and Norton™ consumer products, as well as additional third-party data sources. Symantec also gathers malicious code intelligence from more than 130 million client, server, and gateway systems that have deployed its antivirus products. Additionally, the Symantec distributed honeypot network collects data from around the globe, capturing previously unseen threats and attacks and providing valuable insight into attacker methods. Spam data is captured through the Symantec probe network, a system of more than 2.5 million decoy email accounts, Symantec MessageLabs™ Intelligence, and other Symantec technologies in more than 86 countries from around the globe. Over 8 billion email messages, as well as over 1 billion Web requests, are scanned per day across 16 data centers. Symantec also gathers phishing information through an extensive antifraud community of enterprises, security vendors, and more than 50 million consumers.
    [Show full text]
  • Delivering Results to the Inbox Sailthru’S 2020 Playbook on Deliverability, Why It’S Imperative and How It Drives Business Results Introduction to Deliverability
    Delivering Results to the Inbox Sailthru’s 2020 Playbook on Deliverability, Why It’s Imperative and How It Drives Business Results Introduction to Deliverability Every day, people receive more than 293 billion Deliverability is the unsung hero of email marketing, emails, a staggering number that only represents ultimately ensuring a company’s emails reach their the tip of the iceberg. Why? The actual number intended recipients. It’s determined by a host of of emails sent is closer to 5.9 quadrillion, with the factors, including the engagement of your subscribers overwhelming majority blocked outright or delivered and the quality of your lists. All together, these factors to the spam folder. result in your sender reputation score, which is used to determine how the ISPs treat your email stream. Something many people don’t realize is that to the Deliverability is also a background player, so far in the major Internet Service Providers (ISPs) — Gmail, shadows that many people don’t think about it, until Yahoo!, Hotmail, Comcast and AOL — “spam” there’s a major issue. doesn’t refer to marketing messages people may find annoying, but rather malicious email filled with That’s why Sailthru’s deliverability team created this scams and viruses. In order to protect their networks guide. Read on to learn more about how deliverability and their customers, the ISPs cast a wide net. If a works on the back-end and how it impacts revenue, message is deemed to be spam by the ISP’s filters, it’s your sender reputation and how to maintain a good dead on arrival, never to see the light of the inbox, as one, and best practices for list management, email protecting users’ inboxes is the top priority of any ISP.
    [Show full text]